+1 for this. I bought two boxes of the 1 oz Fiocchi 12LRSLUG from Cheaper Than Dirt, and became disappointed when they didn't fit in my new 4x4 shell carrier. You can stuff them in, but good luck getting them out fast. I was more disappointed when i shot them, because they where very accurate in my 930 JM Pro and very comfortable to shoot.
Not only that, but you may not get yer 8/9/x rounds in yer tube either. Ask me how i know...